Define how the image is anchored to the viewport bounds
By default, its upper-left corner is anchored to the viewport bounds upper left corner.
The anchorPoint is a unit vector where each component falls in range [0.0,1.0].
Some common examples:

Define the image scrolling ratio
Scrolling speed is defined by multiplying the viewport delta position (e.g. followed entity) by the specified ratio.
Setting this vector to <0.0,0.0> will disable automatic scrolling.
To specify a value through Tiled, use one of the following format :

a number, to change the value for both axis

a json expression like json:{"x":0.5,"y":0.5} if you wish to specify a different value for both x and y

Default Value:

<1.0,1.0>

repeat :String

Define if and how an Image Layer should be repeated.
By default, an Image Layer is repeated both vertically and horizontally.
Acceptable values :

'repeat' - The background image will be repeated both vertically and horizontally